Green Extraction of Carotenoids from Fruit and Vegetable Byproducts: a review

Figure 1. Representative chemical structures of carotenoids. 
1.1. Characteristics of Carotenoids 
Carotenoids are classified as fat-soluble micronutrients, characterized by a broad 
spectrum of health-promoting properties. An increased carotenoid content in the daily 
diet may reduce the risk of chronic conditions, such as cancer or coronary heart disease 
[3]. Carotenoids have strong antioxidant, anti-inflammatory and anticancer effects (pre-
venting lung, breast, prostate, colorectal and ovarian cancer). Carotenoids have been 
proven to have a protective effect on cardiovascular disease. The consumption of pro-
cessed tomato products contributes to lowering the susceptibility of lipoproteins to oxi-
dative damage, thus preventing hypertension and atherosclerosis. Furthermore, carote-
noids help to reduce oxidative stress, which contributes to osteoporosis. The relationship 
of lycopene in blood serum with the risk of the disease has also been investigated. It was 
found that its presence is directly related to a reduced risk of osteoporosis. In addition, 
carotenoids play a key role in strengthening the immune system. Studies have shown that 
the daily consumption of beta-carotene helps to improve the activity of natural killer (NK) 
cells [3]. Moreover, beta-carotene is a precursor of vitamin A, whose deficiency in pre-
school children and pregnant women can result in blindness, poor growth, or even death. 
Vitamin A is essential for maintaining normal vision and the prevention of eye diseases. 
Of particular importance in this regard are two carotenoids: lutein and zeaxanthin, whose 
effects have been documented in the prevention of macular degeneration (AMD), the 
leading cause of vision loss in people over 65 years of age [4]. Additionally, some of the 
carotenoids consumed with the daily diet accumulate in the skin and effectively protect it 
from harmful UV radiation, such as damage, burns, and skin aging [4]. Unfortunately, 
excess carotenoids can also be harmful. Too much lycopene in the diet can cause an orange 
discoloration on the skin. This phenomenon is referred to as lycopenodermia. A similar 
phenomenon is carotenoderma, which manifests as yellow spots on the skin and is caused 
by excessive levels of carotenoids in plasma. This condition can be achieved by a daily 
intake of more than 30 mg of beta-carotene over a long period of time. Other adverse risks 
from excess carotenoids in the diet are reproductive disorders, leukopenia, allergic reac-
tions and increased risk of prostate cancer [3].